Deploy a Dockerized Application to Azure Kubernetes Service using Azure YAML Pipelines 2 – Terraform Development Experience

Posted by Graham Smith on April 7, 2020No Comments (click here to comment)

This is the second post in a series where I'm taking a fresh look at how to deploy a dockerized application to Azure Kubernetes Service (AKS) using Azure Pipelines after having previously blogged about this in 2018. The list of posts in this series is as follows:

  1. Getting Started
  2. Terraform Development Experience (this post)
  3. Terraform Deployment Pipeline
  4. Running a Dockerized Application Locally
  5. Application Deployment Pipelines
  6. Telemetry and Diagnostics

In this post I take a look at how to create infrastructure in Azure using Terraform at the command line. If you want to follow along you can clone or fork my repo here, and if you haven't already done so please take a look at the first post to understand the background, what this series hopes to cover and the tools mentioned in this post. I'm not covering Terraform basics here and if you need this take a look at this tutorial.

Working With Terraform Files in VS Code

As with most code I write, I like to distinguish between what's sometimes called the develop inner loop and the deployment pipeline. The developer inner loop is where code is written and quickly tested for fast feedback, and the deployment pipeline is where code is committed to version control and then (usually) built and deployed and subjected to a variety of tests in different environments or stages to ensure appropriate quality.

Working with infrastructure as code (IaC) against a cloud platform is obviously different from developing an application that can run completely locally, but with Terraform it's reasonably straightforward to create a productive local development experience.

Assuming you've forked my repo and cloned the fork to a suitable location on your Windows machine, open the repo's root folder in VS Code. You will probably want to install the following extensions if you haven't already:

The .gitignore file in the root of the repo contains most of the recommended settings for Terraform plus one of my own:

The following files in the iac folder are of specific interest to my way of working locally with Terraform:

  • Here I declare variables here but don't provide default values.
  • terraform.tfvars: Here I provide values for all variables that are common to working both locally and in the deployment pipeline, and which aren't secrets.
  • dev.tfvars: Here I provide values for all variables that are specific to working locally or which are secrets. Crucially this file is omitted from being committed to version control, and the values supplied by dev.tfvars locally are supplied in a different way in the deployment pipeline. Obviously you won't have this file and instead I've added dev.txt as a proxy for what your copy of dev.tfvars should contain.
  • Here I specify the minimum versions of Terraform itself and the Azure Provider.

The other files in the iac folder should be familiar to anyone who has used Terraform and consist of configurations for the following Azure resources:

With all of the configurations I've taken a minimalist approach, partly to keep things simple and partly to keep Azure costs down for anyone who is looking to eek out free credits.

Running Terraform Commands in VS Code

What's nice about using VS Code for Terraform development is the integrated terminal. For fairly recent installations of VS Code a new terminal (Ctrl+Shift+') will create one of the PowerShell variety at the rood of the repo. Navigate to the iac folder (ie cd iac) and create dev.tfvars based on dev.txt, obviously supplying your own values. Next run terraform init.

As expected a set of new files is created to support the local Terraform backend, however these are a distraction in the VS Code Explorer. We can fix this, and clean the Explorer up a bit more as well:

  1. Access the settings editor via File > Preferences > Settings.
  2. Ensuring you have the User tab selected, in Search settings search for files:exclude.
  3. Click Add Pattern to add a glob pattern.
  4. Suggested patterns include:
    1. **/.terraform
    2. **/*.tfstate*
    3. **/.vscode
    4. **/LICENSE

To be able to deploy the Terraform configurations to Azure we need to be logged in via the Azure CLI:

  1. At the command prompt run az login and follow the browser instructions to log in.
  2. If you have access to more than one Azure subscription examine the output that is returned to check that the required subscription is set as the default.
  3. If necessary run az account set --subscription "subscription_id" to set the appropriate subscription.

You should now be able to plan or apply the configurations however there is a twist because we are using a custom tfvars file in conjunction with terraform.tfvars (which is automatically included by convention). So the correct commands to run are terraform plan -var-file="dev.tfvars" or terraform apply -var-file="dev.tfvars", remembering that these are specifically for local use only as dev.tfvars will not be available in the deployment pipeline and we'll be supplying the variable values in a different way.

That's it for this post. Next time we look at deploying the Terraform configurations in an Azure Pipeline.

Cheers -- Graham

Continuous Delivery with Containers – Amending a VSTS / Docker Hub Deployment Pipeline with Azure Container Registry

Posted by Graham Smith on December 1, 2016No Comments (click here to comment)

In this blog series on Continuous Delivery with Containers I'm documenting what I've learned about Docker and containers (both the Linux and Windows variety) in the context of continuous delivery with Visual Studio Team Services. It's a new journey for me so do let me know in the comments if there is a better way of doing things!

In the previous post in this series I explained how to use VSTS and Docker to build and deploy an ASP.NET Core application to a Linux VM running in Azure. It's a good enough starting point but one of the first objections anyone working in a private organisation is likely to have is publishing Docker images to the public Docker Hub. One answer is to pay for a private repository in the Docker Hub but for anyone using Azure a more appealing option might be the Azure Container Registry. This is a new offering from Microsoft -- it's still in preview and some of the supporting tooling is only partially baked. The core product is perfectly functional though so in this post I'm going to be amending the pipeline I built in the previous post with Azure Container Registry to find out how it differs from Docker Hub. If you want to follow along with this post you'll need to make sure  you have a working pipeline as I describe in my previous post.

Create an Azure Container Registry

At the time of writing there is no PowerShell experience for ACR so unless you want to use the CLI 2.0 it's a case of using the portal. I quite like the CLI but to keep things simple I'm using the portal. For some reason ACR is a marketplace offering so you'll need to add it from New > Marketplace > Containers > Container Registry (preview). Then follow these steps:

  1. Create a new resource group that will contain all the ACR resources -- I called mine PrmAcrResourceGroup.
  2. Create a new standard storage account for the ACR -- I called mine prmacrstorageaccount. Note that at the time of writing ACR is only available in a few regions in the US and the storage account needs to be in the same region. I chose West US.
  3. Create a new container registry using the resource group and storage account just created -- I called mine PrmContainerRegistry. As above, the registry and storage account need to be in the same location. You will also need to enable the Admin user:

Add a New Docker Registry Connection

This registry connection will be used to replace the connection made in the previous post to Docker Hub. The configuration details you need can be found in the Access key blade of the newly created container registry:


Use these settings to create a new Docker Registry connection in the VSTS team project:


Amend the Build

Each of the three Docker tasks that form part of the build need amending as follows:

  • Docker Registry Connection = <name of the Azure Container Registry connection>
  • Image Name = aspnetcorelinux:$(Build.BuildNumber)
  • Qualify Image Name = checked

One of the most crucial amendments turned out to be the Qualify Image Name setting. The purpose of this setting is to prefix the image name with the registry hostname, but if left unchecked it seems to default to Docker Hub. This causes an error during the push as the task tries to push to Docker Hub which of course fails because the registry connection has authenticated to ACR rather than Docker Hub:


It was obvious once I'd twigged what was going on but it had me scratching my head for a little while!

Final Push

With the amendments made you can now trigger a new build, which should work exactly as before except now the docker image is pushed to -- and run from -- your ACR instance rather than Docker Hub.

Your next question is probably going to be how can I get a list of the repositories I've created in ACR? Don't bother looking in the portal since -- at the time of writing at least -- there is no functionality there to list repositories. Instead one of the guys at Microsoft has created a separate website which, once authenticated, shows you this information:


If you want to do a bit more you can use the CLI 2.0. The syntax to list repositories for example is az acr repository list -n <Azure Container Registry name>.

It's early days yet however the ACR is looking like a great option for anyone needing a private container registry and for whom an Azure option makes sense. Do have a look at the documentation and also at Steve Lasker's Connect(); video here.

Cheers -- Graham